Control system.



PATENTED NOV. 7, 1905.

C. W. LARSON.

CONTROL SYSTEM.

APPLICATION FILED AYB.17,1905.

2 SHEETS-SHBBT l.

Witnesses. Inventor: Cari W. Larson.

No. 803,834. PATENTED NOV. 7, 1905. c. w. LARSON.

CONTROL SYSTEM.

APPLICATION FILED APR.17,1905.

2 SHEETS-SHEET 2.

Fig.5.

Witnesses. I Inventor: 1 Carl \M Larson.

NITED STATES-- PATENT OFFICE.

CARL LARSON, OF SCHENECTADY, NEIV YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEIV YORK.

CONTROL SYSTEM.

Specification of Letters Patent.

Patented Nov. 7, 1905.

To all whom it may concern:

Be it known that I, CARL W. LARSON, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Control Systems, ofwhich the following is a specification.

The present invention relates to control apparatusfor electric motors.Where the mechanism or apparatus to be operated by the motor or motorsis normally held by looks or brakes, it is imperative that these looksor brakes be released before current is supplied to the motor or motors,since otherwise serious injury might result. In one of its aspects thepresent invention may be regarded as comprising means associated withmotor-control apparatus for preventing current from being supplied to amotor or motors until all locks, brakes, or other restricting devicesare released.

In some cases it is necessary that control apparatus forindependently-operated parts be so related to each other that a definitesequence in the positioning of the parts must be maintained. In rollinglift-bridges, for example, care must be taken when-closing the bridgethat the leaves be brought down in proper order. hen separate motors areemployed for operating the leaves, they must be controlled in such amanner that an improper sequence in the closing movements of the leavesis impossible. In another aspect the present invention relates to meanswhereby the proper sequence of movement of two separately operatedelements is automatically brought about.

The present invention in these and other aspects will be more clearlyunderstood in connection with the following description thereof.

In the accompanying drawings, Figure 1 illustrates the electricalequipment for two bridge-leaves arranged in accordance with the presentinvention. Figs. 2 and 3 show, respectively, a closed bridge and apartly-open bridge, together with a portion of the control apparatusassociated therewith. Fig. A shows a portion of the controller and incross-section the controller-locking arrangement. Fig. '5 is a plan viewof the parts shown in Fig. A, with the upper cap on thecontroller-handle removed.

Similar reference characters will be used throughout the specificationand drawings to indicate like parts.

The present invention is illustrated specifically as embodied inbridge-controlling apparatus and will be described in detail, it being,however, understood that this particular embodiment is simplyillustrated as one of the uses to which the invention may be placed.

Separate motors and separate control apparatuses are provided for thetwo bridgeleaves, and the motor-controller is arranged to have aslight'preliminary movement for energizing the bridge-lock andbrake-coils before the motor-circuit is completed. A looking deviceadjacent the controller looks it against further movement until alock-releasing device is energized by current flowing through a circuitwhich is completed only when all the bridge-locks and brakes are inreleased positions. I have further provided means for opening themotor-circuits whenever the bridge members occupy either the full openor full closed position, this being accomplished by providing auxiliaryswitches which energize circuit breaker tripping means at the properpoints. In addition I have provided auxiliary switch mechanism wherebyone bridge-leaf automatically stops at a predetermined point of itsclosing movement in case it precedes the other bridge-leaf in reachingthat point, but does not stop in case the other bridge-leaf has reachedthat position first.

The bridge-leaves A and B are provided with interlocking projections aand b, the projection a being adapted to rest upon the projection b whenthe bridge is lowered, and therefore the leaf B must be lowered first.

M M are two motors which are arranged to operate the bridge-leaves B andA, respectively. C and C are controllers for the motors M and M.

D and D are circuit-breakers arranged to connect the motor H and themotor M, respectively, to current-supplying mains.

E and E are reversing-switches.

L L and L L are locks adapted to engage, respectively, with the leaves Band A.

F and F are brakes adapted to bring the motors M and M to rest oninterruption of current. i

The controllers C and C may be of any usual type. That illustratedconsisting of a cylinder carrying contact-segments which are adapted tofirst complete the motor-circuit through a series of resistance-sectionsand then to cut out the resistance-sections one at a time until themotors are connected across the line with no resistance in circuit.Since the two controllers are similar to each other, only onenamely,C-will be described. In

. addition to the usual controller-contacts I have provided a pair ofelongated fixed contacts 0 0, together with a pair of connected movablecontacts 0 and 0 the arrangement of contacts being such that thecontacts 0 and 0* engage with the contacts 0 and 0 before any of themain controller-contacts come into operative engagement with each other.The function of these auxiliary contacts is to complete a circuitfromline 1 through the circuitbreaker D, wire 3,the releasing-coils ofthe lock L and brake F, wire 4, to line-wire 2. The first movement ofthe controller-handle therefore serves to energize the lockreleasing andbrakereleasing coils, whereby the bridge member and the motor becomefree to move when current is supplied to the motor. The controller isprovided with a lock, to be hereinafter described, which permits thecontroller to be moved only from the OE position to a position justshort of the first running position. This lock is released when the coilK is energized. The circuit of the coil K passes through auxiliarycontacts Z which are closed when the locks L and the brake F are intheir retracted positions. As soon, therefore, as the bridge-locks andbrake have been retracted the coil K is energized, and the controller isfree to move to its various running positions. If, however, any one ofthe bridge-locks or the brake fails to release, the circuit for thelock-releasing coil K remains interrupted, and the controller remainslocked, thereby preventing current from being supplied to the motoruntil the operator finds the defect and remedies it.

The circuit-breaker D is provided with a tripping-coil (Z, which may beenergized in several different ways, thereby tripping thecircuit-breaker, interrupting the motor-circuit, and permitting thebrake F to be applied. The coil d is connected directly across the linethrough the reversing-switch and a doublethroW switch G, the movablemember of the switch G being connected to the bridge, so that when thebridge is in its lower position the circuit is completed through thefixed contacts g and when the bridge is in its upper position to thecontacts g. lonsequently the tripping-coil (Z is energized and themotorcircuit automatically interrupted whenever the bridge-leaf Breaches its full-open or fullclosed position.

Assuming that the bridge-leaf is in its lower position and it is desiredto raise it, the reverser is thrown so as to bring the movable contactsa and 6 into engagement with the fixed contacts 6 and 0 Thecircuit-breaker D may be closed and will remain closed because thecircuit of the tripping-coil (Z is interrupted at the lowermost of thefixed contacts e of the reversing-switch. The motor M may now beoperated to raise the leaf. When the leaf is fully raised, however, thecontact 9 is bridged, and the circuit for the tripping-coil (Z iscompleted through these contacts and through the two upper of the seriesof fixed contacts a which are bridged by the movable contact 6. Thetripping-coil is therefore energized and the circuit-breaker tripped.When it is desired to lower the bridge-leaf, the reversing-switch ismoved to its lowering position, and the circuit of the tripping-coilwill remain interrupted until the switch G is moved to bridge thecontacts g, which occurs when the bridge-leaf is fully lowered.

Since the two bridge-leaves are operated by separate motors andcontrollers, it may happen that the leaf A may be lowered ahead of theleaf B to such a point that the end of the leaf B cannot pass the end ofthe leaf A unless means is provided for preventing this. To this end Ihave arranged an additional circuit for energizing the tripping-coil (Zof the circuit-breaker D'namely, through switches H and H,which areoperated, respectively, by the leaves B and A during their opening andclosing movements. hen the two bridgeleaves are lowered, the switches Hand H are respectively open and closed, as shown. As the bridge-leavesopen, however, the switch H is closed and the switch H opened, thisoccurring when the bridge-leaves are in such a position that theirmeeting ends are free to interlock. hen both switch H and H are closed,a circuit is completed for the coil (1 from wire 1, breaker D, throughcoil cZ, wire 5, switch H, wire 6, switch H, wire 4 to line 2. It isevident that both switches can be closed at the same time only in casethe leaf A in its lowering movement closes the switch H before the leafB has descended far enough to again open the switch H. hen this happens,the circuit-breaker D will be tripped and the leaf A brought to restuntil the leaf B can be brought to the interlocking position. In case,however, the leaf B descends slightly ahead of the leaf A thecircuit-breaker D is not tripped and the leaf A continues its movementto its lowered position. In case it is desired to compel the leaf B tostop at an intermediate point when lowered a switch It may be associatedwith the switch H, the switch 7t serving to close a circuit fortripping-coil (Z from line 1, tripping-coil (Z, wire 7, switch S, andswitch /t to whet to line-wire 2. The switch S must be opened when thebridge is being raised and closed only after the bridge has passed thepoint at which the switches H and it are operated.

In Figs. 4 and 5 I have shown the mechanical construction of a portionof the controller C, including the auxiliary contacts 0 to c and thelocking device. This auxiliary mechanism is illustrated as forming anattachment to an old form of controller; but it is obvious that it maybe arranged within the main controller-casing and form part of thecontroller. 8 is the controller-shaft, and 9 is a controllerhandleconnected to the shaft 8 by means of a short shaft 10. 11 is a casingsecured to the top of the controller-casing in any suitable manner, soas to have its wall 12concentric with the shafts 8 and 10. The fixedcontacts 0 and c are arranged within casing 11 and insulated therefromby means of the insulation 13. The shaft 10 carries an arm 14, on oneend of which are mounted the movable contacts 0 and 0 which, as the armis rotated, engage with the fixed contacts 0 and 0'. Upon the end of thearm 14: opposite the contacts 0 and 0 is arranged a spring-actuated dog15, which when the controller-handle is turned in a clockwise directionengages with a shoulder 16, projecting inwardly from the casing 11 andlocks the controller against further movement. In this position ofthecontroller the contacts 0 and c are in engagement with the contacts 0and 0; but the main controllercontacts have not yet comeinto operativeengagement. The dog 15 forms the armature of a magnet of which the coilK is the energizing-coil. Therefore when the coil K is energized in themanner previously described the dog 15 is attracted sufliciently to passthe shoulder 16namely, to release the controller and permit it to bemoved into and through its various running positions. If desired, thecontacts 0 and 0 may be connected by means of coil 0", whereby amagnetic field is set up about the contacts 0 0 which serves tointerrupt any arc which may be formed upon moving these contacts into orout of engagement with the cooperating contacts 0 0. A spring 17 issecured at one end to the casing 11 and at the other end to the arm 14,the arrangement being such that when the controllerhandle is turned thespring is placed under tension and serves to return the controllerhandleto its off position as soon as the controller-handle is released.

It will now be seen that the present invention provides a simple andefficient form of bridge-operating apparatus in which it is impossibleto injure the operating-motors by supplying them with current before alllocks and brakes are removed and whereby the leaves are compelled toclose in proper succession. At the same time the leaf which must reachits lowered position last does not necessarily stop at an intermediatepoint, but does so only when the other leaf gets behind, therebyenabling the bridge to be closed in the shortest possible time. Withslight alterations the system disclosed may of course be made applicableto the control of movable parts other than bridgeleaves, and, moreover,although I have shown my improved controller in connection with aparticular system of control, it is evident that the controller may beused in quite different systems of control and independently of theapparatus, which relates specifically to bridge control or to thecontrol of a plurality of interdependent members or parts.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. In combination, a part to be moved, a lock therefor, a motor, amotor-controller, a lock for said motor-controller, and means controlledby the lock for the part to be moved for releasing said controller-lock.

2. In combination, a part to be moved, a lock therefor, amotor-controller, a lock for said motor-controller, and means forreleasing the controller-lock when the lock for the part to be moved isin its retracted position.

3. In combination, a motor, a brake therefor, a controller, a lock forpreventing the controller from completing the motor-circuit, and meanscontrolled by said brake for releasing the lock.

4:. In combination, a motor, a brake therefor, a controller, a lock forpreventing the controller from completing the motor-circuit. and means.for releasing said look when the brake is in its retracted position.

5. In combination, a part to be moved, a lock therefor, a motor, amotor-controller, means controlled by the controller in moving from itsoff position to its, circuit-closing position for releasing said look, astop for preventing the controller from passing into the circuit-closingposition, and means controlled by said locl; for retracting said stop.

6. A controller comprising brake-controlling contacts andmotor-controlling contacts, a stop for normally preventing thecontroller from closing the motor-controlling contacts, and anelectromagnet for controlling said stop.

7. A controller comprising arotatable member having brakecontrollingcontacts and motor-controlling contacts, cooperating contacts soarranged that the brake-circuit is closed before the motor-circuit, astop which normally prevents the controller from moving to themotor-circuit-closing position, and electromagnetic controlling meansfor said stop.

8. In combination, a part to be moved, a lock therefor, a motor, acontroller having lock-controlling and motor-controlling positions, astop which normally prevents the controller from assuming themotor-controlling position, and means controlled by said lock forrendering said stop inoperative.

9. In combination, a part to be moved, a lock therefor, a motor, acontroller comprising a rotatable member having lock-controlling andmotor-controlling contacts, cooperating contacts so arranged that thelock-circuit is closed before the motor-circuit, means for normallypreventing said controller from IIO - electromagnetic stop forpreventing said motor-controller from closing the motor-circuit, anelectromagnet for controlling said step, and a switch for controllingsaid electromagnet associated with said look. A

1-2. In combination, a part to be moved, a lock therefor, a motor, amotor-controller, a stop for preventing said motor-controller fromclosing the motor-circuit, an electromagnet for controlling said stop,and a switch associated with said lock for completing a circuit throughsaid electromagnet when the lock is retracted.

13. In combination, a part to be moved, a lock therefor, a motor, acontroller comprising lock-controlling contacts and motor-controllingcontacts, thearrangcment being such that the lock-controlling contactsare closed before the motor-controlling contacts, a stop for preventingthe motor-controlling contacts from closing, an electromagnet forcontrolling said stop, and means controlled by said look when in itsretracted position for energizing said electromagnet.

14. In asystem of control, a pair of members to be moved, separatemotive and control apparatus therefor including means controlled by eachmember for rendering its motive apparatus inoperative at predeterminedpoints, and means for automatically stopping one of said members at anintermediate point when it precedes the other member to said point.

15. In a system of bridge control, a pair of bric ge-leaves, separatecontrol apparatus for each leaf, and means for automatically stoppingone of said leaves at an intern'iediate point in its closing movementwhen ithas preceded the other leaf to said point.

16. In a system of bridge control, a pair of bridge-leaves, separatemotive and control apparatus for each leaf including means controlled byeach leaf for stopping its motive apparatus when the leaf is infull-open or in full-closed position, and means for stopping the motiveapparatus of one of said leaves at an intermediate point when itprecedes the other leaf to that point.

17. In a system of bridge control, a pair of bridge-leaves, separatemotive apparatus for each leaf, means for rendering the motive apparatusof each leaf inoperative when the leaves reach their full-open orfull-closed positions, means for automatically stopping one leaf at apredetermined point in its closing movement, and means for bringing theother leaf to rest at said point only when it is the first to reach saidpoint.

18. In a system of bridge control, a pair of bridge-leaves, separatemotors for operating said leaves, a circuit-breaker arranged in thecircuit of the operatingmotor for one of said leaves, tripping means forsaid circuitbreaker, a normally open and a normally closed switchcontrolling said tripping means,

and operative connections between said switches and the bridge-leaveswhereby each switch is actuated when its respective bridgeleafapproaches a predetermined angle, the arrangement being such that thecircuitbrealier is tripped when both switches are closed, whereby themotor-circuit of one leaf is opened and the leaf stopped at anintermediate point when the leaves descend in a certain order.

In witness whereof I have hereunto set my hand this 15th day of April,1905.

CARL \V. LARSON. Witnesses:

BENJAMIN B. HULL, HELEN Oaronn.

